I. Field of the Invention
This invention relates generally to materials handling equipment, and more particularly to the design of side curtains for use with conveyor belts used for transporting bulk materials for inhibiting spillage of the granular material.
II. Discussion of the Prior Art
Rubberized fabric conveyor belts are commonly used for transporting bulk materials, such as sand, gravel, iron ore, taconite and similar materials. Likewise, conveyor belts are commonly used in the grain milling industry for transporting granular materials.
A problem often arises at a location along the conveyor belt where the bulk material of the type described is dispensed from a hopper or chute onto the conveyor belt because of a tendency for the bulk material to overflow the side edges of the conveyor belt. This is especially true if the flow rate from the hopper is not properly matched to the speed of the conveyor belt. To avoid the attendant mess and need for frequent cleanup, an economical means must be provided for inhibiting spillage of the bulk material off from the side edges of the conveyor belt onto which the bulk material is being deposited.
The prior art teaches a variety of conveyor belt side curtains, also commonly referred to as skirt boards, and in this regard, reference is made to the Stahura U.S. Pat. No. 4,236,628, which became Reissue U.S. Pat. Re. No. 31,249. It comprises a plurality of relatively narrow (6" wide) interlocking skirt board sections having dove-tail grooves formed therein so as to mate with corresponding dove-tail shaped, outwardly projecting ribs on a mounting plate. The interlocking skirt board members have a lower edge that is adapted to cooperate with a moving conveyor belt when the mounting plate is appropriately suspended from a frame system. The narrow rubber blocks comprising the skirt members fail to properly seal in that the blocks tend to fall off their mounts and leakage occurs at the numerous joints. Other patents directed to conveyor belt side curtains include deRooy U.S. Pat. No. 5,303,813, Mott U.S. Pat. No. 5,154,280, Swinderman U.S. Pat. Nos. 5,048,669 and 4,874,082, Gordon U.S. Pat. No. 4,231,471, and Klegg U.S. Pat. No. 3,499,523.
Each of these patents describes side curtains or skirt boards having a stationary mounting plate and a displaceable skirt whose lower edge is brought into contact with a moving conveyor belt to inhibit spillage of granular material off the sides of the conveyor. The need still exists, however, for a less expensive skirt board design that provides ease of mounting relative to a conveyor system and ease of adjustment of the skirt board member at periodic intervals to accommodate wear of the skirt board and an ability to conform to curves in conveyor belts such as commonly occurs at transition areas where the belt leaves a tail pulley and crosses an adjacent troughing roller. The present invention provides such an improvement.